Skip to main content

Full text of "Text Book Of Mechanical Engineering"

1180

Appendix  VL

Putting ^ = i for initially dry steam, and inserting all other
values, #2 may be found. The pressure energy changing into its
equivalent of kinetic, we have thenó

Energy delivered up to any point   =   Kinetic energy received

where Sa and S2 are the sensible, and Lj and L2 the latent heats,
# the dryness, and J = 774.

Now take a series of pressures, and tabulate the kinetic energy
and the velocity at each pressure.
Next,

Area x velocity = specific volume x dryness

and,    Area in sq. ins.

144 "V",#

The values of p, v, and a are finally plotted as in Fig. 1036,
on a base of kinetic energy. Two important results may
be deduced : (i) the vertical #/through 15 Ibs. pressure divides
the base into 135,000 and 115,000 foot pounds, the first of which
is performed before reaching atmospheric pressure, while the